Spark plug



J. SHARP ET AL.

SPARK PLUG Feb. 13, 1923.

FILED MAR. 19, 192i.

Patented Feb. 13, 1923.

UNITED STATES JOHN SHARP AND WILLIAM SHARP, OF CLEVELAND, OHIO.

SPARK PLUG.

Application filed March 19, 1921.

To all 4.0 710m it may concern Be it known that we, JOHN SHARP and WILLIAM SHARP, citizens of the United States, and residents of Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in, Spark Plugs, of which we hereby declare the following to be a full, clear, and exact description, such as will enable others skilled in the art to which it appertains to make and use the same.

The objects of the invention are to provide an improvement in means for attaching terminals for spark plugs, by means of which a rigid connection is made for the central terminal with the central insulation, and a ri id ground terminal is provided which Wlll not change its form under all working conditions of temperature or rough usage. Also, simple and eflicient forms of construction are provided for both terminals, which can easily and conven iently be constructed and assembled Further, the invention includes a simple, rigid and serviceable means for attaching the central insulated terminal to the central insulation without screw-threading the connected parts and without expensive machining of any kind while being made.

The invention is hereinafter described, shown in the accompanying drawings, and specifically pointed out in the claims.

In the accompanying drawings, Fig. 1. is a. side elevation of the device; Fig. 2 is a longitudinal central section of the device; F ig. 3 is a perspective of the connection for the central terminal, shown in Fig. 2; Fig. 4 is a section showing a modified form of connection for this purpose; Fig. 5 is a bottom view showing the connection for the ground terminal; Fi 6 is a plan of a modified form of groun terminal; Fig. '7 is a perspective of an integral terminal shown in Fig. 5; Fig. 8 is a perspective of a twopiece terminal shown in Fig, 5; Fig. 9 is a plan of a modified form of anchoring Sillt for the central terminal, shown in Fig. 4; Fig. 10 is a perspective of the skirt: Fig. l]. is a section showing a screw connection for the parts.

In. these views, A is the metal body of the plug; B is the central insulation; 0' is the packing nut; D is the central insulated terminal; and E is the ground or body terminal.

The central insulated terminal is formed Serial No. 453,647.

of a rod of sparking alloyed metal, and its outer end is embedded in the metal head, F, WlllCll rests upon the outer end of the insulation, B, and is rigidly secured and anchored thereto, so that the internal pressure upon the rod will not force it out of the insulation, and the action of the binding nut, G, when it is tightened to secure the circuit wire, H, will not loosen it.

In Figs. 2 and 3, one form of anchor is shown, and in Figs. 4, 9 and 10, another form is shown.

In Fig. 3, a slotted skirt, I, is shown, attached to the head, H, which may be made of cheaper and dissimilar metal.

This skirt is provided with a shoulder, J, which is retained within the annular groove, K, by means of a heat-resisting and selfhardening cement at L, which flows through the slot, L.

In Figs. 4;, 9, and 10, the skirt, M, is punched from sheet metal and provided with dovetailed extremities, between which the cement will flow, and when hardened will prevent longitudinal or rotary movement of the head.

This skirt is preferably attached to the head by means of a central eyelet, O, which is integrally attached to the head, by turning its edge over the horizontal disc portion, 0 of the skirt, which is provided with an opening, 0, through which the eyelet passes.

Also, the inner edge is forced, by means of a punch applied at P, P, over the edge of the disc, 0 thus locking the head and skirt together and preventing the rotation of the head on the skirt.

In Figs. 5, 6, 7, and 8, the ground terminal, E, is shown.

This terminal is provided with a diamond shaped or elongated opening, R, therein, through which the insulated terminal projects This gives a wide active surface for engaging the discharge of the spark from the central terminal, and the shape insures complete rigidity of the terminal and also provides for the free and complete circulation of gas thereabout, and also its vertical sides present narrow surfaces upon which the oil will not be retained, and .is easily cleaned.

The electric contact is also perfect at both ends, S, which are inserted in slotted openings, T, cut in opposite sides of the inner end of the body of the spark plug.

In Fig. i. the parts of the tri -meet are ;-;ho\ .n integral and. are stamped iii-om one it flat metal stamppiece of met l; in Fig. i, inn is shown.

lhe rigidity o't this l the (u .nond or and the edjustnhilit the length oi the so by bendinc; the end o, i tifilillllnill. D, toec rds r en 1'; rowing (iXtl'El'IlltlGS of the ground terminal.

The walls 016 the opening T. T present shoulders which prevent the teiininnl from shifting in either direction.

In Fig. 11; modified term of shown, Where the shirt, I '5 f'QQUl'OCl by (e-- inent, shown in Fig. unl t. passing); through it secures the Wire churn inggnuts, F and G, in place. I

The centre]. terminal. ll. is the head of the screw at l).

en d .1 scrc embedded in liming described the in whnt no claim as new and: d sire to seem'e h is depth in o sides oi: said inet'rl body and the central port-ions ot the flat metal sides oi? said 'round terminal separated to enclose said 'Jdl terminal between. therein.

2. In a spark plug in combination with the metal body central insulation and central terminal a. tint motel ground terminal termed in two duplicate portions and having its extremities embedded in opposite aides of said hotly said portions turned upon their edges and engaging each other at eeoh and and having; their 'euti portions sepz rated to enclew said i trel terminal:

T .iinet'eu. -with .n e r l: plug, the weird and central insuletion of a hel et heed provided with en (1111- V 'd skirt provided with leternl ipening seidl insulation PlOVlEletl. with en annular slot in its outer end, in which shirt is emheeded end self hardening cement. in said slot said cement forming means for loclo" said shirt and head seid insulation.

In at spark plug, the combination with the metal. body and central insulation, of a, cent-rel terinineh a head provided with rm. ennulnrsltirt said. skirt provided with lateral openings saidinsuletion nrovided with en annular slot in outer end, in which said szrirt is embedded, and: a self hardening cement in said slot said. cen'ient forming; means tor locking said sl 'irt and head in sa d in ulation, and o. for .itt'acliingg the skirt to said heed.

iony whereof. we hereuntose= our this 1st day of Jllnreh, 1921..

JOHN SHARP, WILLIAM SHARP.

In presence ott- "NM; lire ion,

iiior, W. l i YMA'N.

hotly hands 

